Deducing relationship from DNA results for two matches at two different websites?

Can you share Centimorgans and not be related?

Since DNA is inherited randomly, even a sibling may share more, or less, DNA with a relative than you do. A centimorgan can only tell you how much DNA you share with a genetic relative. There may be multiple genealogical relationships that can share the same amount of DNA.

How many Centimorgans do 1st cousins share?

You usually share about 850 cM with a first cousin, but that number could be as low as 553 or as high as 1,225 cM. Likewise, a single shared-cM value could indicate a variety of relationships. For example, 1,200 shared cM could indicate a first cousin, great-grandparent, grandparent, or great-niece.

How many Centimorgans do half second cousins share?


Relationship Range in percentages
1st cousin; Great-grandparent / Great-grandchild; Great-Uncle/Aunt Great Nephew / Niece 4% – 23%
1st cousin once removed; half first cousin 2% – 11.5%
2nd cousin 2% – 6%
2nd cousin once removed; Half 2nd cousin 0.6% – 2.5%

Can you share DNA with someone and not be related?

Yes, it is possible to share a small amount of DNA with someone and not be related. In other words, it’s possible to share genetic material and not share a common ancestor or any identifiable genealogical connection.

How many centimorgans should full siblings share?

3500 centimorgans

Siblings share around 50% of their DNA while half siblings only share around 25%. The amount shared is usually expressed in something called centimorgans. Full siblings tend to share around 3500 centimorgans while half siblings share closer to 1750.

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